On Thu, Apr 14, 2011 at 9:11 AM, Max <[email protected]> wrote:
>
> Terry,
> I do not confess to be anywhere near an expert, but layer2 is, as far
> as I know based on a hash of the MAC addresses
>
> http://www.linuxfoundation.org/collaborate/workgroups/networking/bonding
>
> So how well things are balanced depends on the how many machines are active
> to/from a server, what their MAC addresses are, and how these MAC addresses
> hash. If you only have a few hosts active then you may end up with only
> one interface being used - things will only really even out if you have
> 'enough hosts' all doing approximately the same amount of work against the
> server, all at the same time.
>
> [Also be aware that using 3 interfaces may not work well with some
> algorithms/
> routers ... I am told that for Cisco's it is best to use 1, 2, 4, or 8
> interfaces
> from the server, otherwise you may never get a balance coming into you
> server]
>
>> ...
>> Transmit Hash Policy: layer2 (0)
>> ...
>>
>> I think the reason why I see one interface dominating RX and another
>> dominating TX is due to the xmit_hash_policy but there are three hosts
>> that use this particular server for network traffic. That's 3
>> different physical mac addresses. The layer2 algorithm should be fine
>> in that situation I would think. What am I missing? Would I just be
>> better off with balance-rr?
>>
> Max
> _______________________________________________

Thanks for the replies.  Ok, good.  At least I have something I can
try.  From what I am seeing, there are two hash algorithms, are there
more?:
layer2
layer3+4

I will try layer3+4 and report back what I see.  I didn't think about
the odd number of interfaces.  The switching stack is brocade.  Since
I can't move to 10G immediately, I am forced to try this other xmit
policy.  If that doesn't work, I will scale back down to two
interfaces on each host and add more hosts.    The application I am
using is truly load balanced active/active/active so it will use all
hosts pretty evenly.  I may open a case with brocade too to see what
they have to say about it.
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